JPH03211129A - Paper feeding device - Google Patents

Abstract

PURPOSE:To perform the delivery of sheets stably by constructing a sheet placing means in such a way as to bring the uppermost sheet of a volume of sheets into contact with a part of the surface of an endless belt when the volume of sheets are placed. CONSTITUTION:A volume of sheets P is placed in such a way that its upper face is in uniform contact with the lower face of an endless belt 1 by lifting a sheet placing member 6. The rotation of the endless belt 1 is started by a tension-driving means 2 on the basis of a sheet feeding start signal. Voltage is applied to the first electrode 12 and second electrode 13 of the endless belt 1 by a voltage applying means 10. This voltage application is performed in its timing controlled by a voltage application control means 11. With the delivery of the sheets, the thickness of the volume of sheets P is decreased, but it is so formed that the upper face of the volume of sheets P and the lower face of the endless belt 1 are always in uniform contact with pressing force within the fixed range, so that the uppermost sheet of the volume of sheets P is always sent out stably.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an automatic paper feeder that uses electrostatic adsorption force in copying machines, printers, etc. It concerns top feeder technology.

(Prior art) Conventionally, when paper is fed by a paper feed belt in copying machines, printers, etc., the common method is to use a rubber belt to press against the paper and use the coefficient of friction of the rubber to feed the paper. Met. Furthermore, in consideration of aging and deterioration of the rubber material, a method is also known in which a belt having a large number of holes is used to suction and feed the paper using a vacuum. Also, in recent years,
In order to improve the shortcomings of these methods, various methods have been proposed for feeding paper using electrostatic adsorption force.

For example, one using an endless belt provided with a pair of comb-shaped electrodes (Japanese Patent Application Laid-open No. 187422/1983), and one using an endless belt provided with a pair of isolated electrodes alternately (Japanese Patent Publication No. 187422/1983). 56058) etc. have been proposed.

FIG. 7 shows an example, in which FIG. 7(a) is a schematic configuration diagram and FIG. 7(b) is a sectional view. The endless belt 1 stretched over the driving roll 2 and the driven roll 3 has a large number of electrodes 71 arranged therein, one end of each electrode is exposed on the back surface of the endless belt, and When the belt is conveyed, a fixed contact piece 73 attached to the support 72 comes into contact with the exposed surface of the electrode and slides, thereby supplying power.

(Problems to be Solved by the Invention) However, conventionally known belt systems using a rubber belt or a vacuum have the problems of lacking stability in paper feeding and increasing noise. Furthermore, even when electrostatic attraction is used, the structure of the endless belt is complicated, and there are problems such as wear of electrodes and contact pieces, spark discharge, etc., resulting in high costs and easy failure. However, it was not yet sufficient for stable paper feeding.

The present invention has been made for the purpose of improving the stability of paper feeding in a top feeder type.

Therefore, an object of the present invention is to provide a paper feeding device that can stably feed paper using a top feeder method.

(Means and Effects for Solving the Problems) A paper feeding device of the present invention includes an endless belt made of a semiconductive resin belt having a first electrode and a second electrode arranged on the back side, and the endless belt. a tension rack/driving means for driving the tension rack and having a power supply mechanism for supplying power to the electrode; a paper mounting member;
The paper mounting member includes a voltage application means for applying a potential difference between the first electrode and the second electrode via the power supply mechanism, and a voltage application control means for controlling the application timing of the voltage. The present invention is characterized in that when the paper tray is placed, the topmost sheet of paper on the paper tray comes into contact with a part of the surface of the endless belt.

In the paper feeding device, the paper tray is placed such that the upper surface of the paper tray uniformly contacts the lower surface of the endless paper plate, for example, by raising the paper placing member. In response to the signal to start paper feeding, the tensioning/driving means starts rotating the endless belt.
A voltage is applied to the electrode and the second electrode by a voltage application means, and the timing of voltage application is controlled by a voltage application control means.

As the paper is fed out, the thickness of the paper tray decreases, but in the paper feeding device of the present invention, the upper surface of the paper tray and the lower surface of the endless belt are always uniformly in contact with the lower surface of the endless belt with a pressing force within a certain range. With this structure, the paper at the top of the paper tray is always fed out stably.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a paper feeding device of the present invention. In FIG. 1, reference numeral 1 denotes an endless belt, which is made of a semiconductive resin belt with a pair of electrode patterns on its back surface.
The drive roll 2, which also serves as a power supply roll, is stretched over a driven roll 3, which also serves as a power supply roll. A retard roll 5 and a feed roll 4 are provided on the downstream side where the paper advances.

Paper plates P are loaded on an elevator tray 6, and are configured such that the upper surface of the paper plate is in constant contact with the lower surface of the endless belt 1. In addition, 7 is a paper detection sensor, 8 is an endless belt support member, 9 is a paper top surface detection sensor, 1
0 is a voltage applying means for applying a potential difference to the electrodes of the endless belt, and 11 is a controller.

FIGS. 2 and 3 are a back view and a perspective view showing the endless belt used in the paper feeding device of the present invention in a stretched state.

In the endless belt, a pair of electrode patterns are printed with conductive ink on the back side of a semiconductive resin belt 16, one electrode 12 is on the high voltage side, and the other electrode 13 is on the low voltage (or ground) side. It is formed to be. The pitch between these electrodes should not be too fine for ease of printing and for the possibility of short-circuiting between the electrodes. As a result of the experiment, 2~LOmm
It has been found that sufficient suction force to feed paper can be obtained in the range of .

The endless belt 1 is stretched around a drive roll 2 and a driven roll 3 made of an insulating elastic body.

A metal roll 21 is coaxially provided on the drive roll 2,
Further, a metal roll 31 is provided coaxially with the driven roll 3, and the metal roll 21 is in contact with the high voltage side electrode supply portion 14 of the endless belt, and the metal roll 31 is
It is arranged so as to be in contact with the low voltage side electrode supply portion 15 of the endless belt. Voltage is applied to these metal rolls 21 and 31 from shafts 22 and 32 in accordance with instruction signals from voltage application control means, thereby creating a potential difference between each pattern electrode of the endless belt.

When paper is sent out by the paper feeding device of the present invention, a voltage is applied to each electrode of the endless belt 1 at a certain timing by the voltage applying means IO according to an instruction from the controller 11 in response to a signal to start feeding the paper. .

As a result, the current forms a circuit that flows from the high-voltage side electrode 12, through the paper in contact with the surface of the endless belt, to the low-voltage side electrode 13, and electrostatic adsorption force is generated, causing the paper to stick to the endless belt. It is attracted and transported. In this case, since electrodes are disposed on the entire back surface of the endless belt, electrostatic adsorption force is generated over the entire surface of the belt.

By the way, since the end portion of the endless belt forms a curved portion, there may be a problem that the paper does not follow the curvature and be separated. Whether or not the paper follows the curvature of the endless belt is determined by the diameters of the driving roll and driven roll on which the endless belt is stretched, but it is within the commonly used roll diameter range of 20 to 40 mm. In this range, the elastic strength of the paper overcomes the electrostatic adsorption force and peels off, so there is no problem. In other words, since the elastic strength (strength of elasticity) of the paper is much larger than the electrostatic attraction force, the paper is separated at the curvature of the end of the endless belt,
There is absolutely no possibility that it will remain adsorbed on the surface without being separated.

Therefore, in the apparatus of the present invention, there is no need to release the electrostatic attraction force between the endless belt surface and the paper at the point where the paper is to be separated (position A in FIG. 1).

Next, the separated paper enters the nip portion between the feed roll 4 and the retard roll 5.

The feed roll 4 is formed by selecting a material that has a higher coefficient of friction with paper than the retard roll 5. For example, the feed roll 4 may contain natural rubber, chloroprene rubber, E
PDM, an elastomer blended with them, and the like are used, and urethane rubber is preferably used for the retard roll 5. The feed roll 4 is configured to rotate in the forward direction of the process, and the retard roll 5 is fixed with a one-way clutch or the like so that it cannot rotate in the transport direction. Therefore, when sheets are fed in duplicate, they can be separated.

When the leading edge of the paper comes out from the feed roll 4 and is detected by the paper detection sensor 7, the application of voltage to each electrode of the endless belt 1 is stopped according to instructions from the controller 11, and the gap between the endless belt and the paper is stopped. The electrostatic adsorption force is released, and the adsorption of the second and subsequent sheets of paper is prevented.

In FIG. 1, the endless belt 1 is supported by a support member 8 that is movable up and down, so that it is always in contact with the surface of the paper with a constant pressing force due to its own weight.

As the paper is conveyed, the support member descends, and the upper surface detection sensor 9 detects the lowering of the support member and issues a detection signal regarding the upper surface position of the paper. In response to the detection signal, a motor (not shown) is driven to move the elevator tray 6 upward and press the paper against the lower surface of the endless belt, so that the paper and the endless belt are kept in constant pressure contact. keep it.

For example, if the accuracy of the top surface detection sensor that steps up the elevator tray is within 0.5 mm, the amount of rise of the elevator tray in one step will also be about 0.5 mm, or about 5 to 7 sheets of paper.
The motor may be controlled to raise the elevator tray every time approximately 5 to 7 sheets of paper are sent out.

In FIG. 1, the feed roll 4 and the retard roll 5 are used as paper separating means, but in another embodiment, a corner separating claw 40 as shown in FIG. 4 may be used. Note that FIG. 4(a) is a diagram showing a state in which corner claws are provided, and FIG. 4(b) is a perspective view thereof. Moreover, a retard pad or a retard plate can also be used instead of the retard roll 5.

FIG. 5 shows another embodiment of the paper feeding device of the present invention, in which the supporting member 8 is fixed and does not move. Note that 50 is a top surface detection sensor, and other symbols have the same meanings as in FIG.

In this embodiment, the upper surface detection sensor 50 is installed on the surface of the paper plate. That is, the upper surface detection sensor 50
When it is off, that is, no paper is detected, it issues a signal to drive the second motor that raises the elevator tray, and when it is on, that is, when paper is detected, it outputs a signal to drive the motor. Set to issue a signal to stop.

In that case, the mounting position of the top surface detection sensor 50 is 0, 1 to 0, which is the distance immediately before the endless belt and the paper come into contact.
．． They may be installed at intervals of 2 mm so that an on signal is output.

In the case of this embodiment, the on/off repeat accuracy of the top surface detection sensor is important, but the conventional two-way signal (on or off) is important.
It is also possible to use a type of sensor that outputs a A signal may be output to stop the motor.

FIG. 6 shows another embodiment of an endless belt that can be used in the paper feeding device of the present invention. In the figure, 60 is a semiconductive resin belt, 61, 62 is a first electrode, 63 is a second electrode, and the first electrode contacts metal rolls 65 provided at both ends of the power supply roll 64. The second electrode is configured to be powered by contacting a metal roll 67 provided at the center of the power supply roll 66 .

(Effects of the Invention) Since the paper feeding device of the present invention has the above-described configuration, it is possible to feed out the paper stably using a single top feeder type paper feeding method.

Therefore, the paper feeding device of the present invention is extremely suitable for use in copying machines and printers.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a paper feeding device of the present invention;
Fig. 2 is a diagram illustrating the back side of the endless belt used in the present invention, Fig. 3 is a perspective view of the endless belt used in the present invention in a stretched state, and Fig. 4 is a diagram showing the corner separating claws. 5 is a schematic configuration diagram of another embodiment of the paper feeding device of the present invention, FIG. 6 is a diagram illustrating another example of the endless belt used in the present invention, and FIG. 7 is a diagram illustrating another example of the endless belt used in the present invention. FIG. 2 is a configuration diagram and a sectional view of a conventional endless belt. 3 1...Endless belt, 2...Drive roll, 3...
Driven roll, 4... Feed roll, 5... Retard roll, 6... Elevator tray, 7... Paper detection sensor, 8... Endless belt support member, 9...
・Top surface detection sensor, 10... Voltage application means, 11.
...Controller, 12.13...Electrode, 14...
High voltage side electrode supply part, 15...low voltage side electrode supply part,
16... Semi-conductive resin belt, 21.31... Metal roll, 22.32... Shaft, 40... Corner separation claw, 50... Top surface detection sensor, 60... Semi-conductive Resin belt, 61.62.63... Electrode, 64
．． 66... Power supply roll, 65.67... Metal roll, 71... Electrode, 72... Support body, 73... Fixed contact piece.

Claims (2)

[Claims] (1) An endless belt made of a semiconductive resin belt with a first electrode and a second electrode arranged on the back surface, and a power supply mechanism for tensioning and driving the endless belt and for supplying power to the electrodes. a tension rack/driving means having a paper mounting member;
The paper mounting means includes a voltage application means for applying a potential difference between the first electrode and the second electrode via the power supply mechanism, and a voltage application control means for controlling the application timing of the voltage. . A paper feeding device characterized in that when a paper plate is placed on the paper plate, the topmost sheet of paper on the paper plate comes into contact with a part of the surface of the endless belt. (2) The paper feeding device according to claim 1, comprising a paper feeding roll and a paper separating means.